1. Field of the Invention
The present invention relates to respiratory interface devices for transporting a gas to and/or from an airway of a user, and, in particular, to a respiratory interface device, such as a mask, that includes a fluid coupling device having various improved exhaust venting mechanisms.
2. Description of the Related Art
A variety of respiratory masks are known which contact the areas of the nose and/or mouth of a human user. The uses for such masks include high altitude breathing (aviation applications), swimming, mining, fire fighting, and various medical diagnostic and therapeutic applications.
In many such applications, a gas is provided at a positive pressure within the mask for consumption by the user. The gas is typically supplied to the user through an air inlet, such as an opening, provided in the mask. In addition, in order to facilitate the delivery of the gas to the mask, a fluid coupling device, such as a swivel conduit, is normally coupled to the air inlet opening of the mask. Specifically, one end of the fluid coupling device is coupled to the inlet of the mask and another end of the fluid coupling device is coupled, perhaps through one or more additional conduits, to an external gas source, such as a blower of a ventilator or other suitable device.
Respiratory masks also often include a mechanism for purging carbon dioxide generated by the user from the mask to the atmosphere. In one known respiratory mask assembly, the venting mechanism is provided in the fluid coupling device (e.g., an elbow device) connected to the air inlet of the mask in the form of a number of vent holes provided directly in the fluid coupling device when it is manufactured, such as by a molding or an assembly process.
As will be appreciated, the particular manufacturing process that is employed places limits on how the vent holes can be formed. For example, in a molding process used to form an elbow device, the shape and particular configuration of the vent holes is limited by the mold. Specifically, due to one or more undercuts, typically included in the mold used to make the elbow device, it may be difficult and impractical to form vent holes in the elbow device which taper from a large diameter on the interior of the elbow device to a smaller diameter on the exterior of the elbow device.
The present inventors recognized that there is room for improvement in the area of masks and similar respiratory interface devices, and, in particular, in the area of achieving a good venting mechanism for exhausting gases such as carbon dioxide generated by the user from the mask to the atmosphere.